Objectives The effect of weekend versus weekday admission following acute coronary syndrome (ACS) on process of care and mortality remains controversial. This study aimed to investigate the ‘weekend-effect’ on outcomes using a multicentre dataset of patients with ST elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction/unstable angina (NSTEMI/UA).
Design This retrospective observational study used propensity score (PS) stratification to adjust estimates of weekend effect for observed confounding. Logistic regression was used to estimate odds ratios (ORs) for binary outcomes and time-to-event endpoints were modelled using Cox proportional hazards to estimate hazard ratios (HRs).
Setting Three tertiary cardiac centres in England and Wales that contribute to the Myocardial Ischaemia National Audit Project.
Participants Between January 2010 and March 2016, 17 705 admissions met the study inclusion criteria, 4327 of which were at a weekend.
Primary and secondary outcomes Associations were studied between weekend admissions and the following primary outcome measures: in-hospital mortality, 30-day mortality and long-term survival; secondary outcomes included several processes of care indicators, such as time to coronary angiography.
Results After PS stratification adjustment, mortality outcomes were similar between weekend and weekday admission across patients with STEMI and NSTEMI/UA. Weekend admissions were less likely to be discharged within 1 day (HR 0.72, 95% CI 0.66 to 0.78), but after 4 days the length of stay was similar (HR 0.97, 95% CI 0.90 to 1.04). Fewer patients with NSTEMI/UA received angiography between 0 and 24 hours at a weekend (HR 0.71, 95% CI 0.65 to 0.77). Weekend patients with STEMI were less likely to undergo an angiogram within 1 hour, but there was no significant difference after this time point.
Conclusion Patients with ACS had similar mortality and processes of care when admitted on a weekend compared with a weekday. There was evidence of a delay to angiography for patients with NSTEMI/UA admitted at the weekend.
- myocardial infarction
- coronary heart disease
- human resource management
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Contributors TK, AGZ and MAM contributed to the acquisition of the data for the analysis. GPM, TK, MS and MAM made substantial contributions to the concept of the work in addition to performing the analysis. GPM and TK drafted the initial version of the manuscript. All authors interpreted the results, revised the paper critically for important intellectual content and approved the final version of the paper. All authors agreed to be accountable for all aspects of the work.
Funding This work was funded by the Medical Research Council through the Health e-Research Centre, University of Manchester (MR/K006665/1) and a grant through the North Staffordshire Heart Committee.
Competing interests None declared.
Ethics approval The National Institute for Cardiovascular Outcomes Research (NICOR) which includes the MINAP database (Ref: NIGB: ECC 1-06 (d)/2011) has support under section 251 of the National Health Service Act 2006 to use patient information for medical research without informed consent. Further ethical approval was not required under current National Health Service research governance arrangements, as all data analysed in the study was pseudonymised and contained no patient identifiable information.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The statistical code used to analyse the data is available upon reasonable request by emailing MAM (corresponding author).
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